Needle cover

ABSTRACT

A single-use cover assembly that obscures a substantial majority or an entirety of an injection needle from view before, during, and after an injection procedure. The cover assembly includes a housing and a needle sleeve that retracts and extends by sliding axially within the housing. The needle sleeve carries a locking collar that moves from a first position to a second position once the needle sleeve is fully retracted. In the first position the locking collar allows retraction of the needle sleeve from a fully extended position. In the second position, a portion of the locking collar covers a tip of the needle, thereby preventing retraction of the needle sleeve from the fully extended position.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.12/474,980, filed May 29, 2009, titled NEEDLE COVER ASSEMBLY FOR ASYRINGE, which claims the benefit of U.S. Provisional Patent ApplicationNos. 61/058,165 filed Jun. 2, 2008 and 61/138,786 filed Dec. 18, 2008.The entire contents of each of the foregoing applications areincorporated by reference herein and made part of this specification.

BACKGROUND OF THE INVENTION

The present invention relates to needle covers and needle coverassemblies for syringes.

Syringes are used throughout the medical industry for the injection andwithdrawal of a wide variety of fluids and solutions into and from thehuman body. Because of the numerous potential hazards associated withthe handling and manipulation of bodily fluids, and particularly blood,there are a number of known safety features that are frequentlyincorporated into various types of syringes and syringe needles. Forexample, many syringe needles are provided with a removable cap thatgenerally prevents needle sticks while the cover is in place. When thecap is removed the needle is exposed. These caps must be removed beforean injection procedure and replaced after the injection procedure beforediscarding the needle. This removal and replacement procedure creates arisk of accidental needle sticks.

Syringes and syringe needles are also frequently configured such that atleast the needles are disposable, that is, they are intended to be usedonly once and then thrown away. This procedure reduces the likelihood oftransferring blood or tissue-born diseases from one patient to another.To this end, many syringe needles are configured to be quickly andeasily detached from an appropriately configured syringe body. In thisway, the syringe body may be reusable, and made of a relatively durablematerial, such as metal, while the disposable needle assemblies may bemade of plastic or other similar, relatively inexpensive, materials.

SUMMARY OF THE INVENTION

In some embodiments, the invention provides a needle cover apparatus forattachment to a syringe needle. The needle defines an axis and includesa distal tip. The needle cover apparatus includes a base and a sleeve.The sleeve includes a distal end defining an opening and is supported bythe base for movement between an extended position in which the sleevecovers the distal tip of the needle and a retracted position in whichthe distal tip extends through the opening. The needle cover apparatusalso includes a locking member that is supported by at least one of thebase and the sleeve. The locking member is moveable relative to thesleeve and includes a locking portion that moves into axial alignmentwith the distal tip and the opening in response to movement of thesleeve from the retracted position to the extended position. Movement ofthe locking portion into axial alignment with the distal tip and theopening prevents subsequent movement of the sleeve to the retractedposition.

In other embodiments, the invention provides a needle cover apparatusfor attachment to a syringe needle. The needle defines an axis andincludes a distal tip. The needle cover apparatus includes a base and asleeve that is supported by the base and that includes a distal enddefining an opening. The sleeve is axially moveable only once relativeto the needle from an extended position wherein the distal tip of theneedle does not extend through the opening, to a retracted positionwherein the distal tip extends through the opening, and back to theextended position. The sleeve is biased toward the extended position.The needle cover apparatus also includes a locking member that ismoveable relative to the sleeve and that includes a locking portion thatmoves to cover the opening in response to movement of the sleeve fromthe retracted position to the extended position. When the lockingportion moves to cover the opening it prevents subsequent movement ofthe sleeve to the retracted position.

In still other embodiments, the invention provides a needle coverapparatus for attachment to a syringe needle. The needle defines an axisand includes a distal tip. The needle cover apparatus includes a basethat defines a central chamber. The central chamber receives a portionof the needle. The needle cover apparatus also includes a sleeve that issupported by the base and that is at least partially received by thecentral chamber. The sleeve defines a needle chamber that receives theneedle. The sleeve also includes a distal end defining an opening thatcommunicates with the needle chamber, and is axially moveable between anextended position in which the distal tip is positioned within theneedle chamber and does not extend into the opening, and a retractedposition wherein the distal tip extends through the opening. The sleeveis biased toward the extended position. The needle cover apparatus alsoincludes a locking member that is received by the needle chamber andthat includes a body portion through which the needle extends. Thelocking member includes a resilient arm that extends distally from thebody portion, and a locking portion that is formed at an end of the arm.The locking member is moveable relative to the sleeve between a firstposition and a second position. When the sleeve is in the extendedposition and the locking member is in the first position, the lockingportion is offset from the axis and positioned proximally of the distaltip. When the sleeve is moved from the extended position to theretracted position, the locking member moves from the first position tothe second position. When the sleeve subsequently returns to theextended position with the locking member in the second position, thelocking portion moves into alignment with the axis and is positioneddistally of the distal tip, which prevents subsequent movement of thedistal tip through the opening.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a needle and needle cover assembly.

FIG. 2 is a plan view with portions illustrated in a section taken alongline 2-2 of FIG. 1, and illustrating the needle and needle coverassembly with a cover removed and a needle sleeve and locking collar ina ready-for-use, first extended configuration.

FIG. 3 is a plan view similar to FIG. 2 and illustrating the needlesleeve and locking collar in a first retracting position.

FIG. 4 is a plan view similar to FIG. 2 and illustrating the needlesleeve and locking collar in a second retracting position in which thelocking collar has engaged a needle base.

FIG. 5 is a plan view similar to FIG. 2 and illustrating the needlesleeve in a third retracting position in which the locking collar isstill engaged with the needle base.

FIG. 6 is a plan view similar to FIG. 2 and illustrating the needlesleeve in a retracted position in which the locking collar has becomecoupled for axial movement with the needle sleeve.

FIG. 7 is a plan view similar to FIG. 2 and illustrating the needlesleeve and locking collar in a first extending position.

FIG. 8 is a plan view similar to FIG. 2 and illustrating the needlesleeve and locking collar in a second extending position.

FIG. 9 is a plan view similar to FIG. 2 and illustrating the needlesleeve and locking collar in a use-prevention, second extendedconfiguration.

FIG. 10 is a perspective view illustrating an alternative needle coverassembly including a two-piece dosing cap with a tip cap in an openposition.

FIG. 11 is section view taken along line 11-11 of FIG. 10 andillustrating the alternative needle and needle cover assembly includingthe two-piece dosing cap with the tip cap in place and covering the endof the needle sleeve.

FIG. 12 is a section view similar to FIG. 11 and illustrating thealternative needle and needle cover assembly including the two-piecedosing cap with the tip cap in the open position and the needle sleeveand locking collar retracted to a first retracting position forextraction of a dose from a vial.

FIG. 13 is a section view similar to FIG. 11 and illustrating the needlesleeve in a retracted position similar to that illustrated in FIG. 6, inwhich the locking collar has become coupled for axial movement with theneedle sleeve.

FIG. 14 is a section view similar to FIG. 11 and illustrating the needlesleeve and locking collar in a use-prevention, second extendedconfiguration.

DETAILED DESCRIPTION

It is to be understood that the invention is not limited in itsapplication to the details of construction and the arrangements of thecomponents set forth in the following description or embodiments, orillustrated in the drawings. The invention is capable of otherembodiments and of being practiced or being carried out in various ways.Also, it is to be understood that the phraseology and terminology usedherein is for the purpose of description and should not be regarded aslimiting.

FIG. 1 illustrates a needle cover assembly 10 that may be removablycoupled to a standard or specially configured syringe assembly (notshown). The cover assembly 10 includes features and components,discussed below in detail, that generally hide the needle from viewbefore, during, and after an injection procedure, thereby reducing oralleviating at least some anxiety or fear that might otherwise be feltby certain patients or other individuals upon seeing the exposed needle.The cover assembly 10 also includes features and components that preventthe cover assembly 10 and associated needle from being used more thanonce.

Although the illustrated cover assembly 10 is configured to be coupledto and removed from a syringe assembly, the cover assembly 10 mayinstead be integrally formed with the syringe assembly. In either case,the syringe assembly is generally of a known type suitable for thewithdrawal and injection of fluids or other solutions from and into thebody by way of the cover assembly 10. In the illustrated construction,the cover assembly 10 includes a base in the form of a generallycylindrical housing 14 that defines a central axis 18. The housing 14defines or is coupled to a needle hub 22 that can be configured foreither removable or permanent attachment to the syringe assembly, orthat may be integrally formed with the syringe assembly. For example,the needle hub 22 may include internal or external threads or othersuitable coupling, latching, or locking features such as tabs, slots,projections, pressure/snap fits, and the like, which may be provided invarious combinations on various portions of the needle hub 22 forcoupling to the syringe assembly. The coupling features engagecorresponding features provided on the syringe assembly to removablycouple the cover assembly 10 to the syringe assembly. Alternatively, theneedle hub 22 may be permanently fixed (e.g. by sonic welding,adhesives, pressure/snap fits, or the like) or integrally formed withthe syringe assembly. In the embodiment of FIG. 1, the cover assembly 10also includes a one-piece, one-part cap 26 that is removably coupled tothe housing 14. Other embodiments, discussed below, include multi-pieceand/or multi-part caps that include a moveable or removable portion toassist in properly drawing a dose from a vial (see FIGS. 10-14).

FIG. 2 illustrates the cover assembly 10 in a ready-for-useconfiguration with the cap 26 removed. The housing 14 is illustrated insection in FIG. 2, revealing that the housing 14 includes upper andlower portions 30, 34 that are coupled to one another by a snap fit,coupling members, sonic welding, or other suitable forms of coupling,depending in part upon the specific material(s) of construction selectedfor the housing 14. In the illustrated construction, the upper portion30 defines a generally cylindrical neck 38 that receives the needle hub22, which may be a standard needle hub manufactured in mass quantity. Inother constructions, the needle hub 22 and the upper portion 30 may beintegrally formed with one another. Regardless of the specificconstruction of the needle hub 22, the needle hub 22 supports a needle42 defining an axis and having a sharpened distal tip 46, which isgenerally configured for insertion into the skin or other tissue of thebody. The needle 42 extends from and through the needle hub 22 for thetransfer of fluid or other solutions between the syringe assembly, whichmay be or include a vial or ampoule and the tip 46.

The needle hub 22 includes a coupling portion 50 that engages thesyringe assembly and the upper portion 30 of the housing 14, and acylindrically reduced support portion 54 that extends axially from thecoupling portion 50 and supports the needle 42. The support portion 54also includes a plurality (e.g. four) of radially and axially extendingribs 58. Each rib 58 includes an axially-facing end surface 62 that issubstantially normal to the central axis 18. The ribs 58 each have asubstantially equal axial length, such that the end surfaces 62 lie insubstantially the same plane.

The lower portion 34 of housing 14 cooperates with the upper portion 30to define a central chamber 66. An end 70 of the lower portion 34includes a radially inwardly extending shoulder 74 that defines anopening 78 that communicates with the chamber 66. The opening 78slidingly receives a needle sleeve 82 that in turn receives and coversthe needle 42. The needle sleeve 82 is substantially cylindrical andincludes an inner end 86 positioned within the chamber 66 and an outerend 90. The inner end 86 includes a radially outwardly extending flange94 that seats against the shoulder 74 of the lower portion 34. The innerend 86 also includes a substantially annular and axially extending rib96 that locates a biasing member in the form of a spring 98. The spring98 engages and extends between the inner end 86 of the needle sleeve 82and the coupling portion 50 of the needle hub 22. The spring 98 biasesthe needle sleeve 82 toward an extended position (FIG. 2) in which theflange 94 of the needle sleeve 82 is biased into engagement with theshoulder 74 of the lower portion 34, and the needle sleeve 82 completelycovers the needle 42. In one exemplary construction, the spring 98 is alinear spring having a free length of about 1.05 inches and a springrate of about 0.7049 pounds per inch. Other constructions may includesofter or stiffer springs depending on the application, and may beconstructed of substantially any suitable material. Progressive springsand/or multiple springs of varying lengths may also be used to provide avariable effective spring rate during movement of the needle sleeve 82between fully extended and fully retracted positions.

As shown in FIG. 1, the cap 26 covers the needle sleeve 82 until the cap26 is removed from the housing 14, preferably just prior to an injectionprocedure. While in place, the cap 26 reduces or prevents contaminationof the needle sleeve 82 and end 70 of the housing 14, for example duringshipping and storage of the cover assembly 10. Unlike many other syringeassemblies, removing the cap 26 before an injection procedure does notexpose the needle 42 because the needle 42 is covered by the needlesleeve 82, as shown in FIG. 2. Furthermore, once the cap 26 is removedit may immediately be discarded because the needle sleeve 82 also coversthe needle 42 once the injection procedure is completed, as discussedfurther below.

The needle sleeve 82 includes an inner surface 102 that defines agenerally cylindrical needle chamber 106. The needle chamber 106 isdivided into an upper chamber 106 a and a lower chamber 106 b by asubstantially annular wall 108 that extends radially inwardly from theinner surface 102. In the lower chamber 106 b, the needle sleeve 82defines a first, generally wedge-shaped recess 110 that is recessed withrespect to the inner surface 102. The first recess 110 is positionedsubstantially adjacent the annular wall 108 and oriented such that thewider portion of the wedge shaped first recess 110 is nearer to theinner end 86 of the needle sleeve 82 and the narrow or pointed portionof the first recess 110 is nearer the outer end 90 of the needle sleeve82.

The needle sleeve 82 also defines a second generally wedge-shaped recess114 oriented similarly to the first recess 110 (e.g. the wide end isnearer the inner end 86 and the narrow end is nearer the outer end 90)and recessed with respect to the inner surface 102. The second recess114 is axially spaced from the first recess 110 and positioned nearerthe outer end 90 of the needle sleeve 82. The first and second recesses110, 114 are substantially radially aligned with one another along theinner surface 102. The needle sleeve 82 also includes a ramp 118 thatextends radially inwardly from the inner surface 102 and is positionedjust above (as viewed in the Figures) the second recess 114.

The outer end 90 of the needle sleeve 82 includes an end wall 122 thatcloses the needle chamber 106 and defines an opening in the form of acentral aperture 126 through which the needle 42 extends when the needlesleeve 82 is retracted, as discussed further below. A plurality ofaxially and radially extending ribs or projections 130 extend from theend wall and away from the needle chamber 106. In the illustratedconstruction, the projections 130 are arranged generally in the shape ofan asterisk that is centered about the central aperture 126. During use,the projections 130 are configured to engage the skin or tissue of apatient just prior to the tip 46 of the needle 42 coming into contactwith the skin or tissue of the patient. In this way, the projections 130apply pressure to the skin or tissue that stimulates the patient'spressure-receptor nerves near the point of insertion of the needle 42.This stimulation of the pressure-receptor nerves competes or interfereswith stimulation of the patient's pain receptor nerves upon insertion ofthe needle 42. In many patients, stimulation of the pressure-receptornerves in this manner reduces the perception of pain during insertion ofthe needle 42.

While the illustrated needle sleeve 82 includes the projections 130described above, a number of other configurations are possible,including a flat end surface, a beveled end surface, differentlyconfigured or arranged projections, and the like. The specificconfiguration of the outer end 90 generally will vary depending upon,among other things, the cover assembly's intended field of use (e.g.,medical, dental, veterinary, and the like).

The outer end 90 of the needle sleeve 82 also includes a guide wall 134that extends axially inwardly from the end wall 122. The guide wall 134includes an arcuate portion 134 a that partially encircles the centralaperture 126, and a support portion 134 b that extends radially from thearcuate portion 134 a to the inner surface 102. The support portion 134b supports the arcuate portion 134 a, and the arcuate portion 134 a inturn supports and guides the needle 42 toward the central aperture 126during retraction of the needle sleeve 82, as discussed further below.

The cover assembly 10 also includes a locking member in the form of alocking collar 138 that cooperates with the needle sleeve 82 to preventmore than a single use of the cover assembly 10, as discussed below. Thelocking collar 138 includes a generally cylindrical body 142 positionedin the upper chamber 106 a and through which the needle 42 extends. Thebody 142 includes a radially outwardly extending flange 146 on one end,and an arm 150 on an opposite end. The arm 150 extends axially away fromthe body 142 through an aperture 152 in the annular wall 108 and intothe lower chamber 106 b. The arm 150 is radially offset from the centralaxis 18 and includes at its distal end a locking portion in the form ofa foot 154 that, in the configuration of FIG. 2, engages a sidewall ofthe needle 42. Engagement of the foot 154 with the needle 42 bends thearm 150 such that the arm 150 diverges away from the central axis 18,with the arm being nearest the central axis 18 adjacent the body 142,and farthest from the central axis 18 adjacent the foot 154. The arm 150is constructed of a suitably resilient material (e.g. plastic) and in amanner such that, in the configuration of FIG. 2, the foot 154 is biasedinto engagement with the needle 42 and the arm 150 seeks to return to arelaxed position in which the length of the arm is substantiallyparallel to the central axis 18.

The locking collar 138 also includes latching tab 158 that extendsradially outwardly from the arm 154 between the body 142 and the foot154. The latching tab 158 extends radially toward the inner surface 102of the needle sleeve 82, and axially toward the body 142 of the lockingcollar 138. In the ready-for-use configuration of FIG. 2, the latchingtab 158 is received by the first recess 110. The arm 150 and thelatching tab 158 together have sufficient resiliency such that thelocking collar 138 moves with the needle sleeve 82 as the needle sleeve82 retracts during use, as discussed further below. The locking collar138, including the body 142, flange 146, arm 150, foot 154, and latchingtab 158 can be fabricated in one piece, and, if desired, from oneuniform material, or may be fabricated from multiple pieces and, ifdesired, from different materials.

FIGS. 3-9 illustrate the cover assembly 10 in various positions duringan operating cycle that proceeds from the ready-for-use extendedconfiguration shown in FIG. 2, to a fully retracted position shown inFIG. 6, and to a use-prevention extended configuration shown in FIG. 9.For clarity, the spring 98 is shown only in FIGS. 2, 6, and 9, whichillustrate the spring in either its expanded or fully compressed state.

Before describing in detail the operation of the cover assembly 10during an injection procedure, it should be noted that both the housing14 and the needle sleeve 82 are preferably constructed of materials thatare translucent, opaque, or otherwise optically distortive, such thatthe needle 42 is not visible to the patient before, during, or after theinjection procedure. Furthermore, aside from the central aperture 126through which the needle 42 extends during the injection procedure, thehousing 14 and needle sleeve 82 are preferably devoid of slots,openings, or other apertures that would allow a patient to see into thehousing 14 or needle sleeve 82 and view the needle 42. Thus, during aninjection procedure, any portion of the needle 42 that does not extendthrough the central aperture 126 will be completely obscured from viewby the housing 14 and needle sleeve 82, and any portion of the needle 42that does extend through the central aperture 126 will be completelyobscured from view because it is inside a vial or inside the patient. Ofcourse, in some instances the entire needle 42 may not be completelyobscured from view throughout the injection procedure depending upon,among other things, the specific shapes of the end wall 122 and theprojections 130, and the angle at which the needle 42 is inserted intothe vial and/or the patient's skin or tissue. Because many people becomeanxious simply at the sight of a needle, the above-described featurescan significantly reduce the anxiety or fear of the patient and/or theperson administering the injection (who may also be the patient in casesof self-injection) to provide a more comfortable overall treatmentexperience.

To further reduce anxiety, particularly in children, the housing 14, cap26, and needle sleeve 82 may be provided with a variety of indicia suchas rainbows, balloons, cartoon characters, or other illustrations thatare generally considered pleasing and comforting to children. In thisway, a child patient may be allowed to choose from a variety ofdifferent cover assemblies 10 prior to an injection procedure. The cap26, in addition or as an alternative to being colored or bearingindicia, may be fabricated to resemble a variety of different cartooncharacters or other objects such that, upon removal from the housing 14prior to an injection procedure, the cap 26 may be presented to a childpatient as a distraction during the injection procedure. When fabricatedto resemble a cartoon character or other object, the size and generallycylindrical shape of the cap 26 make it particularly well suited for useby the child as a finger puppet. Each of these features provides theopportunity to reduce the anxiety or fear experienced by many childrenbefore, during, and after an injection procedure.

FIG. 3 illustrates the cover assembly 10 in a first retracting positionin which the needle sleeve 82 is partially retracted relative to theneedle 42 and the housing 14. The position of FIG. 3 is generallyassociated with a point shortly after the needle tip 46 has pierced theseptum of a vial or the skin or tissue of the patient. The lockingcollar 138 moves together with the needle sleeve 82 toward the needlehub 22 due to engagement between the latching tab 158 and the firstrecess 110 in the needle sleeve 82, which maintains the locking collar138 in a first position relative to the needle sleeve 82. FIG. 4illustrates the cover assembly 10 in a second retracting position inwhich the needle sleeve 82 is further retracted relative to the needle42 and the housing 14, and the flange 146 of the locking collar 138 hasengaged the end surfaces 62 of the ribs 58 provided on the supportportion 54 of the needle hub 22. Engagement of the locking collar 138with the end surfaces 62 of the ribs 58 prevents further axial movementof the locking collar 138 toward the needle hub 22.

As shown in FIG. 5, continued retraction of the needle sleeve 82 beyondthe position illustrated in FIG. 4 results in relative axial movementbetween the needle sleeve 82 and the locking collar 138. Specifically,because the end surfaces 62 of the ribs 58 prevent further axialmovement of the locking collar 138, further retraction of the needlesleeve 82 disengages the latching tab 158 from the first recess 110 andmoves the locking collar 138 away from the first position relative tothe needle sleeve 82. As the locking collar 138 moves axially relativeto the needle sleeve 82, the latching tab 158 slides along the innersurface 102 of the needle sleeve 82 until it engages the ramp 118, asshown in FIG. 5. The resilient nature of the arm 150 and the latchingtab 158 provides resistance to radially inward movement of the latchingtab 158 upon engagement with the ramp 118. This in turn provides aslight but noticeable resistance to further axial movement of the needlesleeve 82. The ramp 118 and the corresponding resistance to axialmovement are provided so that a user who is withdrawing fluid orsolution from a vial or other container for subsequent injection knowsto stop inserting the needle 42 into the vial. By stopping at theposition illustrated in FIG. 5, withdrawing the dose with the syringe,and subsequently removing the needle 42 from the vial, the user avoidsmoving the locking collar 138 into a locked position that wouldotherwise prevent subsequent use of the cover assembly 10 to inject thewithdrawn dose into a patient.

As shown in FIG. 6, the needle sleeve 82 is substantially fullyretracted within the housing 14 and the latching tab 158 has moved intoengagement with the second recess 114 in the needle sleeve 82, such thatthe locking collar 138 is in a second position relative to the needlesleeve. Furthermore, the flange 146 of the locking collar 138 is engagedwith the annular wall 108 of the needle sleeve 82, thereby coupling thelocking collar 138 for axial movement with the needle sleeve 82 in bothaxial directions.

As shown in FIGS. 7 and 8, as the needle sleeve 82 extends from thehousing 14 (e.g., as the needle 42 is withdrawn from the patient), thelocking collar 138 moves axially therewith. It should be noted thatthroughout the range of motion illustrated in FIGS. 2-8, the foot 154 ofthe locking collar 138 slides along the outer surface of the needle 42,and deflection of the needle 42 away from the central axis 18 as aresult thereof is at least partially restrained by the guide wall 134.

As the needle sleeve 82 extends from the housing toward the positionillustrated in FIG. 9, the foot 154 moves distally beyond the tip 46 ofthe needle 42 and the biasing force provided by the resiliency of thearm 150 urges the foot 154 into the use-prevention position illustratedin FIG. 9. In the use-prevention position, the foot 154 moves into axialalignment with the distal tip 46 of the needle 42. Because the lockingcollar 138 is axially fixed relative to the needle sleeve 82, the foot154 also prevents retracting movement of the needle sleeve 82 byengaging the tip 46 of the needle 42 if the needle sleeve 82 is moved ina retracting direction. The foot 154 also overlies the central aperture126 of the needle sleeve 82 to reduce or prevent the dripping of fluidsfrom the needle sleeve 82. Thus, it can be observed that the featuresand components associated with locking the needle sleeve 82 in theextended position after an injection procedure (e.g., the locking collar138, including the body 142, flange 146, arm 150, foot 154, and latchingtab 158, and the first and second recesses 110, 114) are internal to thehousing 14 and the needle sleeve 82.

FIGS. 10-14 illustrate an alternative embodiment of the cover assembly10 that is identified as cover assembly 10 a in FIGS. 10-14. Thefeatures and components of the cover assembly 10 a are similar in formand function to those described above with respect to the cover assembly10, and have been provided with like numerals. To the extent componentsof the assembly 10 a differ slightly from those of the assembly 10, suchdifferences are described and explained below.

FIGS. 10-12 also illustrate an alternative embodiment of the cap 26,identified as cap 26 a in FIGS. 10-14, that may be used to prohibitretraction of the needle sleeve 82 beyond the position illustrated inFIG. 5 during the withdrawal of a dose from a vial prior to aninjection. As discussed above, retraction of the needle sleeve 82 beyondthe position illustrated in FIG. 5 moves the locking collar 138 into alocked position. Thus, if a user is unfamiliar with the syringe assembly10/10 a and is unaware of the significance of the detent resistanceprovided by engagement of the latching tab 158 and the ramp 118 duringretraction, the user may inadvertently insert the needle 42 too far intothe vial such that, upon extraction of the needle 42 from the vial, theneedle sleeve 82 would be locked in the extended position, therebypreventing injection of the newly withdrawn dose.

As shown in FIGS. 10-12 the cap 26 a includes a base cap portion 27 aremovably coupled to the end 70 of the housing 14, and a tip cap portion28 a that is removably coupled to the base cap 27 a. Specifically, thetip cap portion 28 a is connected to a ring portion 164 by a livinghinge 166. The living hinge 166 allows the tip cap portion 28 a to pivotbetween an open position (FIG. 10) and a closed position (FIG. 11). Thering portion 164 fits over a collar 168 defined on an end of the basecap portion 27 a. The collar 168 includes a plurality of radiallyoutwardly extending protrusions 170 that allow the ring portion 164 tobe installed on and removed from the collar 168 if so desired, but thathold the ring portion 164 in place during normal use of the cap 26 aduring dosing and injection procedures. The protrusions 170 also providea slight interference fit with the tip cap portion 28 a to secure thetip cap portion 28 a in the closed position. In alternativeconstructions, the base cap portion 27 a and tip cap portion 28 a may beformed as a single piece. With the base cap 27 a coupled to the housing14 and the tip cap 28 a in the closed position, the cap 26 a completelycovers the needle sleeve 82 to prevent or substantially preventcontamination of the needle 42 and needle sleeve 82, while alsopreventing retraction of the needle sleeve 82.

To draw a dose, a user moves the tip cap portion 28 a to the openposition, thereby exposing the outer end 90 of the needle sleeve 82(FIG. 10). The user then inserts the needle 42 into a vial (not shown)until an end surface 162 of the base cap portion 27 a engages the vial160, thereby prohibiting retraction of the needle sleeve 82 beyond adosing position, which is illustrated in FIG. 12. The end surface 162 ofthe base cap portion 27 a is positioned to allow the needle sleeve 82 toretract a distance sufficient to expose the distal tip 46 of the needle42 for drawing a dose from the vial, while preventing the needle sleeve82 from retracting far enough to move the locking collar 138 into thelocked configuration.

After withdrawal of the dose from the vial, the user removes the needle42 from the vial and the needle sleeve 82 moves back to the fullyextended position. The user may then move the tip cap portion 28 a backto the closed position (FIG. 11) for transportation or storage of thedosed syringe prior to an injection or, if the injection is to occurpromptly after dosing, the user may remove the entire cap 26 a to exposethe remainder of the needle sleeve 82, thereby readying the syringe andcover assembly 10 to administer the injection to a patient in the mannerdescribed above.

It should be appreciated that the base cap portion 27 a may be removablycoupled to the housing 14 by any suitable methods, including snap fits,screw fits, friction fits, and the like. Similarly, the tip cap portion28 a and the ring portion 164 may be removably coupled to the base capportion 27 a, using suitable known methods, such as snap fits, screwfits, friction fits, and the like.

With reference also to FIGS. 11, 13 and 14, it can be seen that thealternative embodiment of the cover assembly 10 a operates insubstantially the same way as the cover assembly 10. FIG. 11 illustratesthe cover assembly 10 a in the ready-for-use configuration with thelocking collar 138 in the first position, similar to FIG. 2. FIG. 13illustrates the needle sleeve 82 substantially fully retracted withinthe housing 14, and the locking collar 138 has moved to the secondposition via engagement with the needle hub 22, similar to FIG. 6.Finally, FIG. 14 illustrates the cover assembly 10 a with sleeve 82returned to the fully extended position and the foot 154 in theuse-prevention position, similar to FIG. 9.

In addition to the features and components discussed above with respectto the cover assembly 10, the lower portion 34 of the housing 14 of thecover assembly 10 a includes axially and radially inwardly extendingribs 172. The ribs 172 are received in corresponding notches (not shown)formed in the flange 94 of the sleeve 82. Engagement between the ribs172 and the notches substantially prevents relative rotation between thesleeve 82 and the housing 14. Also, the upper and lower housing portions30, 34 of the cover assembly 10 a are coupled by a snap fit connection174 positioned proximal the needle hub 22. The upper housing portion 30also includes a plurality of barbs 178 that engage the ribs 58 of theneedle hub 22. The barbs 178 are configured to allow insertion of theneedle hub 22 into the neck 38 of the upper housing portion 30 but toprevent extraction of the needle hub 22 from the neck 38. The neck 38 isalso provided with a shoulder 176 that in some configurations limitsaxial insertion of the needle hub 22 into the neck 38 such that the ribs58 are appropriately positioned relative to the housing 14 to affectmovement of the locking collar 138 from the first position to the secondposition, as discussed above.

The locking collar 138 of the cover assembly 10 a includes an extendedflange 146 relative to the locking collar 138 of the cover assembly 10.The extended flange 146 extends further toward the needle hub 22, whichcompensates for the fact that the needle hub 22 of the cover assembly 10a does not extend as far into the housing as the needle hub 22 of thecover assembly 10. Also, as illustrated, the sleeve 82 of the coverassembly 10 a is formed of multiple pieces, whereas the sleeve 82 of thecover assembly 10 is formed as a single piece.

As discussed above, the needle sleeve 82 is biased to extend from thehousing and cover the needle 42 substantially any time the needle is notinserted into a vial or container for loading the syringe, or into theskin or tissue of a patient during an injection. The cover assembly 10thereby eliminates the periods of needle exposure that occur with manyconventional syringes and syringe shields before loading of the syringe,between loading of the syringe and the injection procedure, and afterthe injection procedure. Eliminating needle exposure also hides theneedle from view throughout the injection procedure, thereby reducinganxiety and fear in patients. Furthermore, once the injection procedureis complete, the needle sleeve 82 automatically extends to cover theneedle 42 and is locked in the fully extended position by the lockingcollar 138, thereby preventing subsequent use of the needle 42.

1. A single-use cover, comprising: a first member generally encompassingto a needle and configured to couple to a medical device configured toperform an injection procedure; a second member configured to moveaxially and rotationally with respect to the first member between afirst position and a second position initially without substantialimpediment, the second member comprising a channel extending along atleast some of the axial length of the second member and configured toreceive the needle such that the first position obscures a distal tip ofthe needle from view; a plurality of projections positioned at a distalend of the second member and configured to inhibit the sensation ofpain; a biasing member configured to bias the second member toward thefirst position; and wherein movement of the second member from thesecond position to the first position automatically engages the leastone locking member to thereby inhibit the second member from returningto the second position.
 2. The cover of claim 1, wherein first memberfurther comprises a radially inwardly extending shoulder and the secondmember further comprises a radially outwardly extending flangeconfigured contact the shoulder.
 3. The cover of claim 2, whereinmovement of the second member from the second position to the firstposition seats the flange against the at least one locking member. 4.The cover of claim 1, wherein the second member is configured to movefrom a third position to the first position without engaging the atleast one locking member, wherein the third position is between thefirst and second positions.
 5. The cover of claim 4, wherein the thirdposition exposes the distal tip of the needle a sufficient distance topierce a septum on a vial.
 6. The cover of claim 4, further comprising acap configured to inhibit the second member from engaging the at leastone locking member.
 7. The cover of claim 1, wherein in the secondposition a distal end of the second member is about even with a distalend of the first member.
 8. A single-use protective cover, comprising: ahousing generally surrounding a needle and configured to connect to asyringe; a sleeve configured to move in a first stage with respect tothe housing between an extended position and a retracted positionsubstantially without impediment, the sleeve comprising a needleaperture and a needle channel extending axially along the sleeve andconfigured to receive the needle such that a distal tip of the needle iscovered by the sleeve in the extended position and is exposed in theretracted position; a biasing member configured to bias the sleevetoward the extended position; wherein a distal end of the sleeve issubstantially flush with a distal end of the housing when the sleeve isin the retracted position; and wherein at least one locking memberengages the sleeve in a second stage as the sleeve moves from theretracted position to the extended position and the engagement obstructsthe sleeve from moving to the retracted position to thereby inhibitreuse of the protective cover.
 9. The protective cover of claim 8,wherein the extended position of the sleeve substantially obscures theneedle from view.
 10. The protective cover of claim 8, wherein movementof the sleeve automatically engages the at least one locking member. 11.The protective cover of claim 8, wherein the cover need not require morethan one hand to operate.
 12. The protective cover of claim 8, whereinthe distal end of the sleeve further comprises a plurality ofprojections configured to engage a patient's pressure-receptor nerves tothereby inhibit the sensation of pain.
 13. The protective cover of claim8, wherein the housing further comprises a radially inwardly extendingshoulder and the sleeve further comprises a radially outwardly extendingflange configured to seat against the shoulder.
 14. The protective coverof claim 8, wherein the flange contacts the at least one locking memberand the biasing member is configured to be biased by the flange and thehousing.
 15. The protective cover of claim 8, wherein movement of thesleeve radially displaces the at least one locking member.
 16. Theprotective cover of claim 8, wherein the sleeve is configured to movefrom a partly retracted position to the extended position withoutengaging the at least one locking member.
 17. The protective cover ofclaim 16, wherein the partly retracted position of the sleeve exposesthe distal tip of the needle a distance sufficient to pierce a septum ona vial.
 18. The protective cover of claim 8, further comprising a capconfigured to limit the retraction of the sleeve to the partly retractedposition to thereby inhibit unintentional engagement of the at least onelocking member.
 19. The protective cover of claim 8, wherein the needlecover is configured to withdraw fluid from a vial without engaging theat least one locking member.